/**
 *    Copyright (C) 2008, 2009  Victor Smirnov <aist11@gmail.com>
 *
 *    This program is free software; you can redistribute it and/or modify
 *    it under the terms of the GNU General Public License as published by
 *    the Free Software Foundation; either version 3 of the License, or
 *    (at your option) any later version.
 *
 *    This program is distributed in the hope that it will be useful,
 *    but WITHOUT ANY WARRANTY; without even the implied warranty of
 *    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *    GNU General Public License for more details.
 *
 *    You should have received a copy of the GNU General Public License along
 *    with this program; if not, write to the Free Software Foundation, Inc.,
 *    51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 *
 *    See LICENSE.exceptions in the root folder of this project for possible
 *    exceptions
 *
 */

#ifndef _CUBEFS_CORE_TOOLS_TYPES_RELATION_FILTER_HPP
#define	_CUBEFS_CORE_TOOLS_TYPES_RELATION_FILTER_HPP

#include <cubefs/core/tools/types/relation/expression.hpp>
#include <cubefs/core/tools/assert.hpp>

namespace cubefs    {
namespace tools     {

template <
        typename Metadata,
        typename Expression,
        typename Relation
>
class Filter {

    CUBEFS_STATIC_ASSERT(IsRelationMetadata<Metadata>::Value);
    CUBEFS_STATIC_ASSERT(IsExpression<Expression>::Value);
    CUBEFS_STATIC_ASSERT(IsList<Relation>::Value);

    template <typename Config, typename Record, typename Accumulator>
    struct Handler {
        static const bool Value = Evaluator<Metadata, Expression, Record>::Value;
        typedef typename IfThenElse<
                    Value,
                    TypeList<Record, typename Accumulator::Result>,
                    typename Accumulator::Result
        >::Result                                                               Result;
    };

    struct Init {
        typedef NullType            Result;
    };

public:

    typedef typename ForEach<
                NullType,
                Relation,
                Handler,
                Init
    >::Result                                                                   Result0;

    typedef typename Result0::Result                                            Result;
};

}
}

#endif //_CUBEFS_CORE_TOOLS_TYPES_RELATION_FILTER_HPP